获取mysql中所有值的总和

Question

假设我有下表。

mysql> desc items; 
+---------------+------------------------+------+-----+---------+-------+ 
| Field   | Type     | Null | Key | Default | Extra | 
+---------------+------------------------+------+-----+---------+-------+ 
| item_value | int(11)    | YES |  | NULL |  | 
| item_quantity | smallint(5)   | YES |  | NULL |  | 
+---------------+------------------------+------+-----+---------+-------+ 

当前的SQL语句是简单的用1

select sum(item_value) as total_value from items where user_id = ? 

量的项目如果某行已超过1个数量，我想考虑到这一点时，我加起来值为所有用户。跟踪每行总数（item_quantity * item_value）还是可以在SQL语句中执行？

Answer 1

你可以做算术的sum()声明：

select sum(item_quantity * item_value) as total_value from items where user_id = ?